Rotary abutment hydraulic pumps and motors



Dec. 10, 1968 w, ADLER 3,415,196

ROTARY ABUTMENT HYDRAULIC PUMPS AND MOTORS Filed Aug. 29, 1966 4 Sheets-Sheet 1 APPLICANT George Fritz Werner Adler BY Mi segades 8c Douglas ATTORNEYS.

Dec. 10, 1968 G. F.-w. ADLER 3,415,195

. ROTARY ABUTMENT HYDRAULIC PUMPS AND MOTORS Filed Aug. 29, 1966 4 Sheets-Sheet 2 Dec.'l0, 1968 G. F. w. ADLER 4 3,415,196

ROTARY ABUTMENT HYDRAULIC PUMPS AND MOTORS Filed Aug. 29, 1966 7 4 Sheets-Sheet 5 Dec. 10, 1968 G. F. w. ADLER 3,415,196

- ROTARY ABUTMENT HYDRAULIC PUMPS AND MOTORS Filed Aug. 29. 1966 4 Sheets-Sheet 4 United States Patent 3,415,196 ROTARY ABUTMENT HYDRAULIC PUMPS AND MOTORS George Fritz Werner Adler, Nether-ton, England, assignor to The English Electric Company Limited, London, England, a British company Filed Aug. 29, 1966. Ser. No. 575,623 Claims priority. application Great Britain, Aug. 27, 1965, 36,895/65; Apr. 14, 1966, 16,473/66 7 Claims. (Cl. 103125) ABSTRACT OF THE DISCLOSURE Rotary abutment hydraulic pumps and motors having cylindrical casing members containing a co-axial lobed member which is driven for rotation about its axis with respect to a casing member, in which a partial cylindrical surface of an abutment member rolls against the partial cylindrical surface of the lobed member lying between projections thereof, and which surfaces are covered with a layer of flexible material which is pinched between the rolling surfaces so as to form an effective seal, the projection on the lobed member being securely fitted to the body of the lobed member and having means so as to prevent momentary short-circuiting of fluid from one side to the other of the projection while the projection is passingsuch rotary abutment.

This invention relates to hydraulic pumps and motors comprising a cylindrical casing member containing a coaxial lobed member consisting of a generally cylindrical body with radially extending projections which, during relative rotation of the casing member and lobed member, sweep through an annular space defined by the casing member and by the body of the lobed member and divided circumferentially into a number of working spaces by spaced abutment members which move to permit each propection to pass successively from one working space to the next.

According to this invention, each abutment member is partly cylindrical with its axis parallel to the axis of the lobed member and casing member, and is driven for rotation about its axis with respect to the casing member at such speed, and is formed with cut-away portions so shaped and dimensioned, that when a projection of the lobed member has passed through a working space from one abutment member to the adjacent abutment member,

the cut-away portion of the adjacent abutment member is r in a position to permit the projection to move past it into the next working space, the part-cylindrical surface of each abutment member being in rolling engagement with part-cylindrical surfaces on the lobed member lying between the projections, a seal between each abutment member and the lobed member being formed during rolling by means of a layer of flexible material which is secured around one or other of the rolling surfaces and is pinched between the rolling surfaces.

Either the lobed member or the casing member may rotate while the other remains stationary.

This invention makes it possible to avoid having any leakage path in the pump or motor obstructed only by line contact between two parts of the pump or motor. That is to say, each seal isolating a space at high-pressure from an adjacent space at low-pressure can be formed by cooperating surfaces of finite length. This saves on expensive high-precision machining. In particular the seal between the part-cylindrical surface of each abutment member and the co-operating surfaces on the body of the lobed member during rolling, which is of finite length because the flexible material can distort, is notably effective in sealing off adjacent working spaces from one another.

The effectiveness of the seals, and particularly the seals between the abutment members and the body of the lobed member, is especially important in the case of larger machines. Moreover, the effectiveness of the seals makes it feasible to run motors according to this invention at very lowspeeds (all the way down to Zero) as well as at higher speeds, at pressures of, for example, up to 1500 pounds per square inch. A motor according to this invention can, for example, be made to run at any speed over a range of say 0 to 30 revolutions per minute, or 0 to revolutions per minute, with a high torque output.

As regards the provision of flexible material on the lobed member, this may be in the form of separate individuals sheets over the different part-cylindrical surfaces between-the projections, or in the form of a single cylindrical sheet with portions cut out where the projections occur. In all cases the flexible sheet material may be bonded to the appropriate part-cylindrical surfaces on the lobed member or abutment members (or on both), which surfaces may be grooved, notched, roughened or otherwise treated to improve adhesion.

Preferably strips of sealing material (for example of Babbitt-metal or similar soft material) are provided on the ends of the projections of the lobed member. These strips may be flexible, though this is not essential. Babbittmetal or similar material may also be provided for sealing on the flat front and back surfaces of the lobed member.

Examples of pumps or motors according to this invention are shown in the accompanying drawings in which:

FIGURE 1 is a section elevation of one example;

FIGURE 2 a partly sectioned end view of the example shown in FIGURE 1; and

FIGURES 3 and 4 are partly sectioned end views of further examples.

FIGURE 1 is a section on the line BB of FIGURE 2 and FIGURE 2 is a section on the line AA of FIG- URE 1.

In FIGURES 3 and 4, parts which are similar to equivalent parts in FIGURE 2 have been given the same reference numerals.

Referring to the drawings, there is provided within a cylindrical casing member 1 a shaft 2 carrying a lobed member 3 consisting of a generally cylindrical body with three projections 31 at to one another. When the shaft rotates, the projections 31 sweep through an an nular space which is defined by the inner surface of the casing member and the outer surface of the lobed member 3. This space is divided into a number of working spaces (in the examples shown there are five working spaces) by means of rotary abutment members 4 of and in the examples illustrated each abutment member rotates at three times the shaft speed.

It will be apparent that with this arrangement the abutment members in effect noll upon the cylindrical surface of the lobed member. They are so phased with respect to one another and to the rotation of the lobed member that, while a projection 31 is sweeping through a working space between one abutment member and the next, that space is sealed off by the cylindrical surfaces of the abut ment members at the two ends of that space. However, by the time the projection has reached the abutment member towards which it is advancing, that member will 'have rotated into a position in which the cut-away portion allows the projection to pass into the next working space.

On each of the three part-cylindrical surfaces on the lobed member lying between the pnojections 31 there is a 3 layer 6 of flexible material (in FIGURES 1 to 3). This layer is preferably composed of oil-resistant synthetic rubber.

Referring particularly to FIGURES 1 and 2 it will be seen that the layers 6 are in the form of strips. The abutment members 4 roll on these strips, and fluid tightness is thus obtained in a simplle manner. Each strip 6 may be bonded to the lobed member in any convenient way. In the example illustrated the lobed member has slots 32 in the root edges of the projections, and the strips 6 are inserted into and stuck into these slots as well as being bonded to the surfaces on which they lie. As will be appreciated, this slot arrangement improves the mechanical strength and durability.

Referring particularly to FIGURE 3 it will be seen that in addition to strips 6, sealing strips 7 of resilient material, again preferably of oil-resistant synthetic rubber, are provided on each side of each part-cylindrical cavity 8 in the casing member 1 in which an abutment member 4 rotates.

Strips 9 of Babbitt-metal may be provided on the partcylindrioal ends of the projections 31'of the lobed member in each example. The Babbitt-metal strips 9 are provided to bed in and subsequently run with fine clearances.

In the example shown in FIGURE 4 it will be seen that the strips 6 of FIGURE 2 are omitted, and instead strips 10 of flexible material, again preferably of oilresistant synthetic rubber, are provided on the part-cylindrical surfaces of the rotary abutment members 4. Again strips 9 of Babbitt-metal may be provided on the projections 31 of the lobed member.

In all the examples illustrated and described above, sealing strips of Babbitt-metal may be applied on the flat front and back surfaces of the lobed member as indicated at 11 in FIGURE 1.

During use, for example as a motor, high-pressure oil is supplied continuously to the trailing sides of the projections of the lobed member, and low-pressure oil is drawn away from the leading sides of the projections (assuming rotation of the lobed member while the casing member remains stationary). For example, assuming clockwise rotation, high-pressure oil is fed in to the working spaces through passages extending from a manifold 47 in the shaft 2, and oil is discharged into a manifold 48 through passages 49.

As has already been mentioned, the lobed member may instead remain stationary while the casing member rotates. In the examples shown that would simplify the connection of the oil-carrying manifolds to the external pipes connected to the oil reservoir and high pressure source.

The flexible sealing layers on the rolling surfaces may be formed by layers of two or more different materials. For example, each layer may consist of a basic layer of oil-resistant synthetic rubber covered by a thin layer which has a low coefficient of friction with the other rolling surface (to reduce friction losses caused by any localised rubbing which may occur between the rolling surfaces owing to distortion of the flexible material) or has a high resistance to wear, or both. The thin layer may, for example, be of metal such as a stainless or other steel or brass, or it may be of a plastic.

As already mentioned, this invention is particularly useful for large motors providing a high torque at low speed. For example, a motor constructed similarly to any of the examples shown in the accompanying drawing and powered by oil at 1500 pounds per square inch may be of a size such as to produce an output torque of 5000 to 50,000 pound feet, or higher. The examples illustrated are intended to produce a torque of 30,000 pound feet.

As a result of this invention, good sealing against working fluid leakage is attained, and there is also economy in manufacture since this invention reduced the closeness of machine tolerances necessary for a given degree of fluid tightness. Also good sealing is retained despite the effects of temperature expansion and contraction over practical working temperature ranges.

In the arrangements illustrated there are three projections on the lobed member and five rotary abutments. Other combinations are also possible. In particular the lobed member may have two diametrically opposed projections with a casing member containing four evenly spaced rotary abutment members.

I claim:

1. An hydraulic machine comprising a cylindrical casing member containing a coaxial lobed member consisting of a generally cylindrical body with radially extending projections which, during relative rotation of the casing member and lobed member, sweep through an annular space which is defined by the casing member and by the body of the lobed member and is divided circumferentially into a number of working spaces by circumferentially spaced rotary abutment members which are shaped to permit each projection to pass successively from one working space to the next, each abutment member being partly cylindrical, with its axis parallel to the axis of the lobed member and casing member, and being mounted for rotation in a recess of part-cylindrical section in the casing member, whereby the part-cylindrical surfaces of the abutment members roll against the part-cylindrical surfaces on the lober member lying between the projections, which surfaces are covered with a layer of flexible material which is pinched between the rolling surfaces so as to form an effective seal, each projection on the lobed member being securely fixed to the body of the lobed member and having a part-cylindrical outer surface which runs close to the inner cylindrical wall of the casing and is of substantial width in a circumferential direction so as to bridge each abutment-containing recess in the casing when the projection is momentarily in alignment with each recess in turn, so as to prevent momentary short-circuiting of fluid from one side to the other of the projection while the projection is passing the rotary abutment.

2. A machine according to claim 1, in which the casing member rotates while the lobe member remains stationary, fluid being fed to and from the working spaces through passages communicating with manifolds formed in a central portion or shaft in the lobed member.

3. A machine according to claim 1 in which the layers of flexible material between the rolling surfaces are on the part-cylindrical surfaces of the body of the lobed member lying between the projections, each part-cylindrical surface having an individual sheet of flexible material of which the ends extend into slots in the roots of the adjacent projections.

4. A machine according to claim 1 in which the flexible material on the rolling surfaces is an oil-resistant synthetic rubber.

5. A machine according to claim 1 in which the lobed member has three projections at intervals and in which there are five rotary abutment members at 72 intervals, each rotary abutment member being driven at a speed which is three times the relative speed between the lobed member and casing member.

6. An hydraulic machine comprising a cylindrical casing member containing a coaxial lobed member consisting of a generally cylindrical body with radially extending projections which, during relative rotation of the casing member and lobed member, sweep through an annular space which is defined by the casing member and by the body of the lobed member and is divided circumferentially into a number of working spaces by circumferentially spaced rotary abutment members which are shaped to permit each projection to pass successively from one working space to the next, each abutment member being partly cylindrical, with its axis parallel to the axis of the lobed member and casing member, and being mounted for rotation in a recess of part-cylindrical section in the casing member, whereby the part-cylindrical surfaces of the abutment members roll against the part-cylindrical surfaces on the lobed member lying between the projections, which surfaces are covered with a layer of flexible material which is pinched between the rolling surfaces so as to form an effective seal, and including means mechanically clamping each flexible layer to the body of the lobed member along parallel axially-extending edges of the flexible layer to retain the flexible layer firmly on the lobed member.

7. An hydraulic machine according to claim 6 in which each projection on the lobed member is securely fixed to the body of the lobed member and has a part-cylindrical outer surface which runs close to the inner cylindrical wall of the casing and is of substantial width in a circumferential direction so as to bridge each abutmentcontaining recess in the casing when the projection is momentarily in alignment with each recess in turn, so

as to prevent momentary short-circuiting of fluid from one side to the other of the projection while the projection is passing the rotary abutment.

References Cited UNITED STATES PATENTS FRED C. MATTERN, JR., Primary Examiner.

WILBUR J. GOODLIN, Assistant Examiner.

US. Cl. X.R. l03l 21 

